U.S. Pat. No. 4,333,830 to H. Michael, 6-8-82, disclosed a vacuum drain system with a series of collection stations.
U.S. Pat. No. 3,224,460 to H. E. Cann III, 12-21-65, disclosed a representative form of ball valve.
Vacuum drain systems with separate electrical or other arbitrary controls of scouring are known.